It is well known to provide watercraft with a pump apparatus for removing bilge water which accumulates in the craft. In its most simple embodiment, such a pumping system incorporates a pump connected through a switch to a power supply. When the bilge water sufficiently collects the switch is manually operated, the pump being operated until the water level is sufficiently lowered. The pump is then switched off. Alternatively, the pump may be provided with a float arrangement allowing some measure of automatic control to the system.
It is also known to provide an electronic sensing apparatus to automatically sense the presence of bilge water and operate the pump.
Often, the bilge water may be contaminated with fuel, which rises to the surface thereof. Activation of a pump in response to a rising level of fuel, rather than water, may have disastrous consequences.
In addition, the natural action of a vessel in responding to waves or swells can cause the bilge water to slop around, creating intermittent contact with sensor probes. Often, the probes are connected to a delay circuit, requiring continuity to be made for a preset length of time prior to pump actuation. In certain circumstances, due to wave action, the probes may not be activated for a sufficient amount of time, thus preventing proper pump action.
It is accordingly the purpose of the present invention to provide a bilge water pump control apparatus which insures a high degree of reliability and accuracy under a variety of operating conditions, and which is capable of distinguishing between the presence of bilge water and fuel.